[Synovial hemangioma of the knee joint--a rare cause of recurrent hemarthrosis].

In the differential diagnosis of bloody knee joint effusions synovial haemangioma as a rare cause has to be considered. Especially suspicious are long durations of disease with recurrent atraumatic blood-stained joint effusions and repeated episodes of painful limitation of motion, laboratory and radiographic findings often being normal. On the one hand arthroscopy can prove the diagnosis by obtaining an ample biopsy specimen, on the other hand it facilitates the healing of the lesion at the same time by radical removal of the tumour.